Recent ozone investigations over Bulgaria by remote sensing: Ground-based and satellite data Original Research Article

This presentation deals with the recent investigations of the dynamics of the total ozone content (TOC) and of the lower troposphere ozone over Bulgaria, South-Eastern Europe. For analysis of the TOC we have used data obtained through measurements carried out by using a ground-based spectrophotometer Photon and data from satellite experiments TOMS-Nimbus 7 and TOMS-EP. The spectrophotometer Photon measures the direct solar ultraviolet (UV) radiation in the range 290–360 nm with 1 nm resolution, using which TOC is calculated. The ozone values received from the ground-based and satellite observations in the period 1999–2005 have been compared. In this period the ozone column did not show a statistically significant trend. The TOC data demonstrated typical for the middle latitudes seasonal variations. The monthly mean ozone values observed during the last 9 years have been examined also. It was found that the largest TOC fluctuations were detected in February and the smallest – in July. Ozone behaviour in the planetary boundary layer (PBL) has been analyzed by using data obtained with remote-sensing technique – ground-based aerosol LIDAR (LIght Detection And Ranging), which give information about the evolution of the PBL. The surface ozone concentrations have been measured with a fast and sensitive ozone monitor, based on chemiluminescent method for ozone detection. The investigation shows that the simultaneous observations of the surface ozone and of the boundary layer dynamics provide the opportunity accurately to establish relation between the BL structure and the features of ozone variations. In particular, the influence of the residual layer on the ozone values near the ground is demonstrated.